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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>promise的all方法</title>
</head>
<body>
<script>
    //·promise.all(）·将多个promsie实例合并成一个新实例
    //只有所有的promise实例的状态都为fulfilled，最终结果才能执行.then
    //如果有一个promise实例的状态为rejected，那么最终结果会执行.catch
    let promise1 = new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(1000);
        }, 1000);
    });

    let promise2 = new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(1000);
        }, 1000);
    });

    let promise3 = new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(1000);
        }, 1000);
    });

    let promise4 = Promise.all([promise1, promise2, promise3])
        .then((res) => {
            console.log(res);
        })
        .catch((err) => {
            console.log(err);
        });
</script>
</body>
</html>